Motor-cycle spring structure



M. L. PREVITALI.

MOTOR CYCLE SPRING STRUCTURE. APPLICATION FILED AusQza, 1920.

1 407 21 Patented Feb,. 21, 1922.

gnaw 01b1 /7. Z. Frau/fabun tes stares irrAnIo L. PBEVITALI, or DENVER,COLORADO.

MOTOR-CYCLE SPRING STRfiCTURE.

mortars.

Application filed August as, 1920. Serial no. 406,688,,

' characters of reference marked thereon,

which form a part of this specification.

The object of this invention is to provide a spring structure for therear of motor cy ole frames whereby said rear may be cushioned fromshocks of travel, as the front of the frame is when provided with.springs on the front forks.

Briefly the invention comprises separating the rear ends of the upperand lower rear forks by means of pins and springs about said pins, therear wheel being supported in the rear ends of the lower rear forks bythe usual wheel-supporting plates. These plates are provided withflanges in which said pins are fixed, the pins at their upper ends beingslidably received in narrow plates secured to the rear ends of the upperrear forks, and said springs being mounted between said flanges and saidnarrow plates.

In the drawings: 3 r

Fig. 1 is an elevation illustrating the application of the invention;

Fig. 2 is an enlarged elevational detail;

Fig. 3 is a similar view of another detail; and Fig. 4 is an elevationshowing a slight modification.

In the form of Figs. 1, 2 and 3, the main frame of the motor cycle isrepresented at 10, the upper rear forks 12 being rigidly connectedthereto adjacent the saddle, while the lower rear forks 14 are pivotallyconnected thereto adjacent the bottom by means of ears 15 on the forksand a pivot pin 16 passing therethrough and through ears 18 on a union20 secured to the frame 10. The rear ends of the forks 14 carry theusual axle-supporting plates 22 having adjusting means 24 forpositioning the axle 25 of the rear wheel 26. The upper edge of eachplate 22 has an outwardly directed horizontal flange 28 which receivesthe reduced lower ends 30 of pins 32 rigidly secured in the respectiveflange 28 by means of nuts or the Specification of Letters Patent. IfPggpt-gntgd like 34-. Saidpins 32 alsov have elongated reduced upperends 35 which pass through corresponding plates 36 rigidly secured tothe rear ends of the upper rear forks 12 and 38 on the reduced ends 35limit the upward rarest resale flying directly above theflanges 28; Nuts1 movement of the plates 36 thereon, while the shoulders 40 at the basesof the reduced por tions 35 limit the downward movement of said plates36. Springs 45 ;mounted upon said pins 32 bear at their opposite endsupon the plates 36 and the flanges 28, and thereby I cushion the rear ofthe machine from shocks resultlng from a rough road. I

In the formof Fig. 4, the mainframe in-., eludes, in addition to theframe part 10, a 1

bracing frame bar 110, which extends from the union 112 at the top offrame 10, where upper forks 12 are joined thereto, to-a union 220 on therear ends of a rigidly mounted rear lower fork-member 114 whose forwardend is secured to frame member 10' by a fixed union 120. vThe member 114is short 7 and to the rear ends thereof immediately behind union 220,the rear ends or extensions 214 of the forks are pivoted at 116. Thisproduces a more rigid structure than that of the other form. Tostrengthen the structure further, a union 50 is secured adjacent therear end of the upper rear forks 12, and v a braceor reinforcing bar52extends from said union 50 down to said union 220, thus so bracing theforks 12 that it will be impos-' sible to bind the parts and preventoperation of the springs 45 due to any possible tendency of the forks 12to spring or yield. Thus the fork extensions will swing about the pivot116 when the springs yield, as do forks 14 about pivot 16 of the otherform.

I claim: I V 1. A spring structure for motor cycles,

comprising a frame, upper rear fork-members rigidly connected-theretoand having their rear ends flattened and provided with an opening, lowerrear fork-members piv otally connected to said frame, an axle plateconnected to the rear end of each rear forkmember, an outwardly directedhorizontal flange at the top of said axle plate, an opening in saidflange, a bolt rigidly secured thereto and projecting through theopening in said flattened portion, a spring surround:

ing said bolt between the flange and the fiat.- tened portion, and meanson said bolt for limiting the distance between said flattened portionand said flange.

iio

2. A bracing frame comprising two tri angles one of which includes aportion of the rear fork-member, a member (52) at right angles to saidlast named member, and a diagonal member (110) joining the lower end ofthe last named member and the upper end of the rear fork-member, thesecond triangle comprising the diagonal member, one side of the mainframe (10) and a tension member (114:), a lower fork-member (214-)pivotally connected to said bracing "frame, an axle plate attachedthereto, an

outwardly extending horizontal flange on the top of said axle plate, andspring means between said flange and the rear end of the upper rearfork-memben 3. A bracing frame consisting of two mom is triangles hayingone side formed by'a common compression member (110), the other twosides of one triangle being formed by a tension member (52) and acompression member (12), the other two sides of the other triangle beingformed by a co1npression member (10) and a tension member (114), a lowerfork member (214-) pivotally connected'to said bracing frame near oneend of the common compression member, an upper fork member forming anextension of the second named compression member (12), and spring meansbetween the lower and the upper fork members. o

In testimony whereof I atfix my signature.

MARIO L. PREVITALI.

